Effect of Nitrogen Starvation on the Responses of Two Rice Cultivars to Nitrate Uptake and Utilization

作     者：YIN Xiao-Ming LUO Wei WANG Song-Wei SHEN Qi-Rong LONG Xiao-Hua 

作者机构：College of Resources and Environmental Sciences Nanjing Agricultural University 

出 版 物：《Pedosphere》 (土壤圈（英文版）)

年 卷 期：2014年第24卷第5期

页      面：690-698页

核心收录：

学科分类：09[农学] 0901[农学-作物学] 0902[农学-园艺学] 090202[农学-蔬菜学] 

基　　金：Supported by the Special Fund for Agro-scientific Research in the Public Interest(No.200903001-5) the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)of China the Natural Science Foundation of Jiangsu Province,China(No.BK2010440) China Postdoctoral Science Foundation(No.20110491439) 

主　　题：nitrate reductase activity nitrate transpoters nitrogen use efficiency Oryza sativa L. remobilization 

摘      要：Ammonium(NH+4) is the main nitrogen(N) form for rice crops, while NH+4near the root surface can be oxidized to nitrate(NO-3)by NH+4-oxidizing bacteria. Nitrate can be accumulated within rice tissues and reused when N supply is insufficient. We compared the remobilization of NO-3stored in the tissue and vacuolar between two rice(Oryza sativa L.) cultivars, Yangdao 6(YD6, indica)with a high N use efficiency(NUE) and Wuyujing 3(WYJ3, japonica) with a low NUE and measured the uptake of NO-3, expression of nitrate reductase(NR), NO-3transporter genes(NRTs), and NR activity after 4 d of N starvation following 7-d cultivation in a solution containing 2.86 mmol L-1NO-3. The results showed that both tissue NO-3concentration and vacuolar NO-3activity were higher in YD6 than WYJ3 under N starvation. YD6 showed a 2- to 3-fold higher expression of OsNRT2.1 in roots on the 1st and 4th day of N starvation and had significantly higher values of NO-3uptake(maximum uptake velocity, Vmax) than the cultivar ***, YD6 had significantly higher leaf and root maximum NR activity(NRAmax) and actual NR activity(NRAact) as well as stronger root expression of the two NR genes after the 1st day of N starvation. There were no significant differences in NRAmax and NRAact between the two rice cultivars on the 4th day of N starvation. The results suggested that YD6 had stronger NRA under N starvation, which might result in better NO-3re-utilization from the vacuole, and higher capacity for NO-3uptake and use, potentially explaining the higher NUE of YD6 compared with WYJ3.